Reference 
This section provides reference materials:
Describes compatibility between different data types when you define data mappings.
Provides a description of all built-in functions in the expression editor.
Provides a description of the generic built-in functions in the expression editor, together with examples.
Example of an EJB Function, Exposed as a Mapping Function
Provides an example of an EJB function that will concatenate two string and then use it within a mapping.